Renamed google.protobuf to protobuf26

third_party/google/protobuf/reflection.py

-# Protocol Buffers - Google's data interchange format
-# Copyright 2008 Google Inc.  All rights reserved.
-# http://code.google.com/p/protobuf/
-#
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are
-# met:
-#
-#     * Redistributions of source code must retain the above copyright
-# notice, this list of conditions and the following disclaimer.
-#     * Redistributions in binary form must reproduce the above
-# copyright notice, this list of conditions and the following disclaimer
-# in the documentation and/or other materials provided with the
-# distribution.
-#     * Neither the name of Google Inc. nor the names of its
-# contributors may be used to endorse or promote products derived from
-# this software without specific prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-# This code is meant to work on Python 2.4 and above only.
-
-"""Contains a metaclass and helper functions used to create
-protocol message classes from Descriptor objects at runtime.
-
-Recall that a metaclass is the "type" of a class.
-(A class is to a metaclass what an instance is to a class.)
-
-In this case, we use the GeneratedProtocolMessageType metaclass
-to inject all the useful functionality into the classes
-output by the protocol compiler at compile-time.
-
-The upshot of all this is that the real implementation
-details for ALL pure-Python protocol buffers are *here in
-this file*.
-"""
-
-__author__ = 'robinson@google.com (Will Robinson)'
-
-
-from google.protobuf.internal import api_implementation
-from google.protobuf import descriptor as descriptor_mod
-from google.protobuf import message
-
-_FieldDescriptor = descriptor_mod.FieldDescriptor
-
-
-if api_implementation.Type() == 'cpp':
-  if api_implementation.Version() == 2:
-    from google.protobuf.pyext import cpp_message
-    _NewMessage = cpp_message.NewMessage
-    _InitMessage = cpp_message.InitMessage
-  else:
-    from google.protobuf.internal import cpp_message
-    _NewMessage = cpp_message.NewMessage
-    _InitMessage = cpp_message.InitMessage
-else:
-  from google.protobuf.internal import python_message
-  _NewMessage = python_message.NewMessage
-  _InitMessage = python_message.InitMessage
-
-
-class GeneratedProtocolMessageType(type):
-
-  """Metaclass for protocol message classes created at runtime from Descriptors.
-
-  We add implementations for all methods described in the Message class.  We
-  also create properties to allow getting/setting all fields in the protocol
-  message.  Finally, we create slots to prevent users from accidentally
-  "setting" nonexistent fields in the protocol message, which then wouldn't get
-  serialized / deserialized properly.
-
-  The protocol compiler currently uses this metaclass to create protocol
-  message classes at runtime.  Clients can also manually create their own
-  classes at runtime, as in this example:
-
-  mydescriptor = Descriptor(.....)
-  class MyProtoClass(Message):
-    __metaclass__ = GeneratedProtocolMessageType
-    DESCRIPTOR = mydescriptor
-  myproto_instance = MyProtoClass()
-  myproto.foo_field = 23
-  ...
-
-  The above example will not work for nested types. If you wish to include them,
-  use reflection.MakeClass() instead of manually instantiating the class in
-  order to create the appropriate class structure.
-  """
-
-  # Must be consistent with the protocol-compiler code in
-  # proto2/compiler/internal/generator.*.
-  _DESCRIPTOR_KEY = 'DESCRIPTOR'
-
-  def __new__(cls, name, bases, dictionary):
-    """Custom allocation for runtime-generated class types.
-
-    We override __new__ because this is apparently the only place
-    where we can meaningfully set __slots__ on the class we're creating(?).
-    (The interplay between metaclasses and slots is not very well-documented).
-
-    Args:
-      name: Name of the class (ignored, but required by the
-        metaclass protocol).
-      bases: Base classes of the class we're constructing.
-        (Should be message.Message).  We ignore this field, but
-        it's required by the metaclass protocol
-      dictionary: The class dictionary of the class we're
-        constructing.  dictionary[_DESCRIPTOR_KEY] must contain
-        a Descriptor object describing this protocol message
-        type.
-
-    Returns:
-      Newly-allocated class.
-    """
-    descriptor = dictionary[GeneratedProtocolMessageType._DESCRIPTOR_KEY]
-    bases = _NewMessage(bases, descriptor, dictionary)
-    superclass = super(GeneratedProtocolMessageType, cls)
-
-    new_class = superclass.__new__(cls, name, bases, dictionary)
-    setattr(descriptor, '_concrete_class', new_class)
-    return new_class
-
-  def __init__(cls, name, bases, dictionary):
-    """Here we perform the majority of our work on the class.
-    We add enum getters, an __init__ method, implementations
-    of all Message methods, and properties for all fields
-    in the protocol type.
-
-    Args:
-      name: Name of the class (ignored, but required by the
-        metaclass protocol).
-      bases: Base classes of the class we're constructing.
-        (Should be message.Message).  We ignore this field, but
-        it's required by the metaclass protocol
-      dictionary: The class dictionary of the class we're
-        constructing.  dictionary[_DESCRIPTOR_KEY] must contain
-        a Descriptor object describing this protocol message
-        type.
-    """
-    descriptor = dictionary[GeneratedProtocolMessageType._DESCRIPTOR_KEY]
-    _InitMessage(descriptor, cls)
-    superclass = super(GeneratedProtocolMessageType, cls)
-    superclass.__init__(name, bases, dictionary)
-
-
-def ParseMessage(descriptor, byte_str):
-  """Generate a new Message instance from this Descriptor and a byte string.
-
-  Args:
-    descriptor: Protobuf Descriptor object
-    byte_str: Serialized protocol buffer byte string
-
-  Returns:
-    Newly created protobuf Message object.
-  """
-  result_class = MakeClass(descriptor)
-  new_msg = result_class()
-  new_msg.ParseFromString(byte_str)
-  return new_msg
-
-
-def MakeClass(descriptor):
-  """Construct a class object for a protobuf described by descriptor.
-
-  Composite descriptors are handled by defining the new class as a member of the
-  parent class, recursing as deep as necessary.
-  This is the dynamic equivalent to:
-
-  class Parent(message.Message):
-    __metaclass__ = GeneratedProtocolMessageType
-    DESCRIPTOR = descriptor
-    class Child(message.Message):
-      __metaclass__ = GeneratedProtocolMessageType
-      DESCRIPTOR = descriptor.nested_types[0]
-
-  Sample usage:
-    file_descriptor = descriptor_pb2.FileDescriptorProto()
-    file_descriptor.ParseFromString(proto2_string)
-    msg_descriptor = descriptor.MakeDescriptor(file_descriptor.message_type[0])
-    msg_class = reflection.MakeClass(msg_descriptor)
-    msg = msg_class()
-
-  Args:
-    descriptor: A descriptor.Descriptor object describing the protobuf.
-  Returns:
-    The Message class object described by the descriptor.
-  """
-  attributes = {}
-  for name, nested_type in descriptor.nested_types_by_name.items():
-    attributes[name] = MakeClass(nested_type)
-
-  attributes[GeneratedProtocolMessageType._DESCRIPTOR_KEY] = descriptor
-
-  return GeneratedProtocolMessageType(str(descriptor.name), (message.Message,),
-                                      attributes)